It is well known to use screws and nails, or similar pin-type fasteners, for securing floor, wall and ceiling panels to supporting structures in buildings and vehicle cargo container bodies. In the case of truck trailer bodies, hard wood floors are attached to a metal frame or substrate. The typical truck trailer body has a steel frame, and the hardwood flooring is secured to the steel frame with metal fasteners. One common technology for securing floors to truck trailer bodies requires pre-drilling holes in both the wood flooring and the underlying metal frame, e.g., steel angle irons and/or I-beams, and applying self-tapping screws through those holes to anchor the flooring to the frame. In some cases, vehicle cargo bodies or personnel-containing structures, e.g., mobile homes, may use aluminum framing. Since aluminum frame members are more easily penetrated than steel frame members of the same thickness, wood flooring and wall and ceiling panels may be attached to aluminum framing by means of nail-type pins with spiral grooves disposed along a portion of their length, with those pins being driven through the flooring and into aluminum frame members by means of a pneumatic high impact driver, e.g., a driver as disclosed in my U.S. Pat. No. 5,645,208, issued 8 Jul. 1997 and U.S. Pat. No. 4,040,554, issued 9 Aug. 1977.
However, applying such pins with a pneumatic high impact driver has limitations with respect to attaching hard wood flooring to steel framing. For one thing, the high impact produced by such a driver tends to split the hardwood flooring. Also, some steel framing members are not readily penetrated by the pins under the force exerted by the high impact driver, particularly when the steel frame members have a thickness of ⅛ inch or greater. Moreover, since it is strictly an impact driving procedure, when a fastener is driven through the flooring member into an underlying steel frame member, the fastener may not be driven in far enough to force the flooring member into a tight fit with the frame, resulting in it not passing inspection requirements. Consequently the procedure using predrilled holes and self-tapping screws has become standard industry practice, even though it is slow due to the need to pre-drill the members to be secured together. Nevertheless, in an attempt to avoid the necessity of pre-drilling the underlying frame members, driver/fastening systems have been conceived whereby special high carbon steel self-drilling wing screws are applied using a high speed screw-driving tool.
One such system is made by Muro Corporation of Tokyo, Japan and comprises its model FLVL41 pneumatic power screwdriver and its Super Wing screws. Those products can be viewed at the web-site “muro.com”. The self-drilling wing screws comprise a forward drill portion, a rearward screw portion, and usually a pair of laterally-projecting wings between the drill and screw portions that serve to form oversize holes in the wood flooring, thereby assuring that the panels will not lift away from the underlying steel frame as a reaction to the rapidly rotating screw portion. The wings break off when they encounter the underlying metal frame members. Such systems are suitable for penetrating mild steel frame members in thicknesses up to about 3/16 inch. However, an impedance to exclusive use of such high speed screw-driving systems using self-drilling wing screws is that trailer body manufacturers are now preferring to use a high tensile strength steel having a tensile strength of 80,000 psi and a yield strength of approximately 50,000-65,000 psi. It is difficult to reliably penetrate that kind of steel in a thickness of ⅛″ using the self-drilling wing screws and a high speed screw-driver. A particular problem is that the fast rotating screws tend to burn due to the heat buildup. Similarly, slow rotating screws do not develop enough torque to penetrate the steel substrate. Therefore, there exists a need for an improved fastening method and apparatus which can reliably attach wood flooring to high tensile strength steel substrates having a thickness in the order of ⅛″ or greater.